Healing wounds is a complex process of tissue repair and regeneration in response to injury. The healing response in skin wounds (Inflammation, proliferation and repair, and tissue remodeling) attempts to reconstitute tissue similar to the wounded one and this is accomplished via the concerted action of numerous skin cell types, collagens, cytokines, growth factors (GF s), chemokines, cell surface and adhesion molecules, as well as multiple extracellular matrix proteins. Skin grafting becomes necessary in many wounds to prevent massive water loss in addition to providing protection against infection during the healing process. Autologous split-thickness skin grafting currently represents the most rapid, effective method of reconstructing large skin defects; however, in cases where a significant quantity of harvested graft is required, it represents yet another trauma to an already injured patient.
Much auto-grafting work has been done previously including our own work and that of others.
Previously, we have described production of a customized skin graft that is preferably accomplished by operation of a three-dimensional printer that is supplied with substrate material and autologous skin cells. The printer then “prints” the supplied skin cells in a particular order, pattern, or by cell type to execute the fabrication of the skin graft. The major objective of the production of a skin graft via 3-Dimensional printing technology is to use the patient's own skin cells to re-create a strong, persistent, organ replacement solution.
The most important and abundant cell type for the development of the autologous skin graft is fibroblast cells. Fibroblasts comprise the bulk of the cells that form and remodel the extracellular matrix and thus, harvesting large numbers for further proliferation and use in the formation of the autologous graft, is essential.
Fibroblasts synthesize substances, including collagen, that form and rearrange the extracellular matrix. They play a crucial role in wound healing and can behave like stem cells capable of phenotypic alteration most commonly to keratinocytes, the primary skin cell type of the epidermal layer. Other fibroblasts are focused on maintenance and tissue metabolism.
In the previous auto-grafting work, as the source of fibroblasts to be autografted onto the patient's wound, standard practice has been to harvest from a donor site selected by the medical practitioner from unwounded dermal tissue elsewhere on the patient, thereby creating a new, additional wound at the donor site in addition to the original wound onto which an autograft is to be placed.